Atomic layer deposition, or ALD, is a manufacturing approach that deposits materials and films in exact places. This can include metals on top of metals, dielectrics on dielectrics, or any other combination. The goal is to reduce or replace the number of patterning steps in the chip or device fabrication process.
In one possible futuristic flow, a tool selectivity deposits a self-assembled monolayer chemistry on a surface. This, in turn, forms a tiny mask or template on the surface at or near perfect alignment.
There also is a direct-write version of ALD, which uses e-beam and multi-beam tools to pattern the surface from the ground up.